Whether arbitrage or manipulation, the Jane Street episode highlights a critical truth: markets need more transparency, more accountability, and more human judgment.

SEBI has banned the firm from India’s securities markets. The drama has thrown a bright light on Jane Street, a company of legendary opacity even in an industry that prioritises secrecy. And it could carry political and regulatory consequences, not just for Jane Street, but for an entire, ascendant industry of marketmakers.

A study by the Securities and Exchange Board of India found that retail investors lost more than $20 billion on option trades over three years. On July 4, SEBI announced it would seize 48.4 billion rupees ($570 million) from trading giant Jane Street Group,